1. Field of the Invention
The present invention relates generally to variable speed transmissions. In particular, the present transmission includes a holding shaft and an apparatus for controlling its rotation to selectively vary the speed of the output shaft.
2. Description of the Related Art
Variable speed transmissions are well-known in the art. Generally, many transmissions include a gearing assembly for transferring the rotational speed of a constant speed input shaft to an output shaft of selectively variable speed. The gearing assembly may include a plurality of sun gears and planetary gears.
U.S. Pat. No. 3,656,363 issued to Defontenay discloses an apparatus for producing intermittent motion. An electric motor is mounted on a frame. A pulley is mounted on the motor shaft and rotates a differential housing inside the frame. A cam follower is in communication with a cam mounted on the housing. The cam follower, having rollers and a gear rack, reciprocates inside the frame. A pinion gear mated to the gear rack of the cam follower is mounted on the same shaft as a first sun gear, which drives a second sun gear through planetary gears. A gear is mated to an output gear and drive output rollers.
U.S. Pat. No. 4,191,070 issued to McKinnis discloses a transmission having a planetary gearing system. A steady-state power source drives an input shaft. Gear arrangements are provided between the input and output shafts. The output shaft is driven and accelerated as a function of a retardation which is supplied to the gear arrangement between the input and output shafts.
It is desirable that a variable speed transmission utilize a constant-speed input source and produce a selectively variable output shaft. Furthermore, it is desirable that a transmission include an apparatus for efficiently and easily varying the speed of the output shaft. It is desirable that a transmission be adaptable to automotive uses as well as other applications.